1. Field of the Invention
The present invention relates to ink jet printing and, more particularly, to ink jet printing for dyeing embroidery thread and to embroidering using thread dyed by ink jet printing.
2. Related Background Art
Apparatus for embroidering a medium such as cloth in accordance with a design generated using a personal computer is known. Such apparatus is advantageous in that it is easy to generate the design and embroidering a complex design can be readily accomplished.
However, the color of the embroidered design depends on the color of thread in the embroidery apparatus. Therefore, when embroidery is carried out using different color threads, the thread used in the apparatus must be changed each time a different color is to be embroidered. To change the thread, the thread currently in the apparatus must be cut and removed, and another thread having a different color must be set in the apparatus and passed through the hole of an embroidery needle. This slows down the embroidery operation and makes it more costly.
Embroidery apparatus for industrial use and sewing machines capable of embroidering are known. However, it is necessary to change an upper thread corresponding to the designated color, so that when multi-color embroidery is performed, it is necessary to design the embroidery pattern taking into account the available colors, and then to embroider in such colors by exchanging the upper thread, as needed. Accordingly, a great deal of time and work is required to embroider in different colors using this technique. In addition, since many threads of various colors must be used, the colors are limited to the number of threads used, and therefore it is difficult to embroider in a large number, say five, colors. For example, when embroidering in colors varying continuously from dark green to yellow, it is necessary to provide threads of numerous colors and change them in accordance with the desired color, and therefore the ability of such embroidery techniques to express color variations is limited.
In recent years, textile printing using ink jet printing techniques has been put to practical use and fine printed material has been readily produced. However, it is difficult with such techniques to provide the three-dimensional effects possible with embroidery.
On the other hand, there is known a thread coloring technique in which warp threads are printed while being transferred from a bobbin to a weaving section to be woven with woof threads. Japanese Patent Publication Kokoku No. Sho 59-42093 discloses an example of such an ink jet thread printing technique. According to this document, an ink discharge nozzle having a diameter of 80 .mu.m discharges ink onto a warp thread utilizing a pressure difference or energy of an electric field or the like to discharge the ink, and the dyed warp threads are then woven with woof threads. In that document, the diameter of the discharged ink droplet is larger than the diameter of the warp thread. As a result, due to overflow and blotting of the ink, the desired fine printing cannot be performed. Moreover, ink cannot be attached on the warp threads uniformly because the ink is applied only when the warp threads are in an upper position relative to the woof threads. In other words, the up-and-down movement of the warp threads significantly affects the precision with which the ink is applied thereto. In addition, the number of ink jet nozzles corresponds to the number of warp threads, making the apparatus large.